I think you are selling yourself short by starting out with fake silencer. Simple aluminum or stainless tubing is the way to go. I get mine from www.onlinemetals.com
Check out http://www.silencertalk.com
for ideas. I have a video posted here for beginners making their own silencers. http://www.youtube.com/watch?v=yYrlxPCmbmU
You have to make it right the first time and replacement parts cannot be made unless you pay another $200 tax. Feel free to PM me.